NEW FIBERBALLS

Abstract: Fiberballs based on poly(1,4-cyclohexanedimethylene terephthalate) fiber have given improved products.

Description: TITLE New FiberbaUs This invention relates to new fiberbaUs, and more particularly to such containing polyester fibers of poly(l,4-cyclohexanedimethylene terephthalate) as polyester polymer, and especiaUy such fiberbaUs as are moldable, on account of containing binder fibers, and their molding into new molded products. Marcus in U.S. Patents Nos. 4,618,531 and 4,794,038 disclosed new fiberbaUs of polyester fibers. In particular, in the latter patent the fiberbaUs were of polyester fibers as load-bearing fibers (sometimes caUed matrix fibers) and of binder fibers, and he disclosed their bonding into molded products and other bonded products. Such fiberbaUs have proved very useful commerciaUy, and improvements and variations have been disclosed in U. S. Patent Nos. 4,940,502, 4,818,599, 5,112,684, 5,154,969, 5,169,580, and 5,218,740, for example. It would be desirable, however, to produce such molded products with better resistance to compression/heat-set than have been available from materials available hitherto. For instance, some seating designers require cushioning materials to take an improved (i.e., numerically lower) set when tested according to ASTM 3574-D, the key test conditions of which require compression to 50% for 22 hours at 158°F (70°C) and allow 30 minutes of recovery time after release from such compression before the "set" is measured. The solution to this problem according to the present invention is provided by fiberbaUs containing binder fibers with load-bearing fibers that consist essentially of poly(l,4-cyclohexanedimethylene terephthalate). This polymer is sometimes referred to herein as CHDMT, as opposed to 2G-T, for poly(ethylene terephthalate), which is the polyester most commonly available and used commercially for polyester fibers hitherto. After solving the above problem by making the present invention, we investigated the cushioning properties of similar fiberbaUs consisting of only CHDMT, i.e., without binder fibers, and found surprising advantages in their properties, mainly in their softness, as wiU be related. According to a first aspect of the invention, therefore, there are provided fiberbaUs, of average diameter 2 to 15mm, consisting essentially of randomly-arranged, entangled, crimped polyester fiberfϊll having a cut length of 10 to 100mm, characterized in that the polyester is poly(l,4-cyclohexane dimethylene terephthalate), and pillows, cushions and other filled articles, in which the filling is, at least in part, such fiberbaUs. According to an important second aspect of the invention, there are provided moldable fiberbaUs, of average diameter 2 to 15 mm, consisting essentially of randomly-arranged, entangled, crimped polyester fiberfill having a -cut length of 10 to 100 mm and including binder fiber, characterized in that said polyester fiberfill consists essentially of poly(l,4- cyclohexanedimethylene terephthalate). Such load-bearing (or matrix) polyester fibers are provided in fiberbaUs with binder fibers, as disclosed by Marcus (referred to hereinbefore) or as will be discussed hereinafter. Preferred binder fibers are bicomponent fibers, of, e.g., sheath/core or side-by-side configuration, having one component (such as the sheath) comprised of lower melting binder material, and the other component (such as the core) preferably comprised also of CHDMT, so as to improve further compression set in the molded products. Preferred binder material should be heat-activatable at a temperature sufficiently higher than 70°C, the test temperature for ASTM 3574-D, i.e., preferred binder material should not be activated under these test conditions, particularly at least 100°C, and especially having a distinct melting point as discussed hereinafter. Also provided, according to other aspects of the invention, are molded products prepared by molding the new moldable fiberbaUs and processes for making the fiberbaUs and/ or molded products. An essential feature of the second aspect of the invention is the use of load-bearing (or matrix) fibers consisting of poly(l,4-cyclohexanedimethylene terephthalate) - CHDMT, instead of 2G-T. In other respects, the disclosures of Marcus and others in U.S. Patents No. 4,794,038, 4,940,502, 4,818,599, 5,112,684, 5,154,969, 5,169,580 and 5,218,740 may essentially be foUowed, in so far as concerns aspects of the invention involving fiberbaUs of load-bearing fibers with binder fibers, and their molding into molded products. Compression/heat-set values were measured accordmg to ASTM 3574-D for several different similarly-prepared and molded fiberball products and are summarized in Table 1, from which it will be seen that the % set values for fiberbaUs of CHDMT polymer according to the invention (Examples 1 and 2) were significantly better (i.e., lower) than for those of 2G-T (Comparisons A-F):- TABLE 1 Matrix em Denier Polymer Crimp Binder Density Set (1) (2) (3) ( ft 3 ) % 1 6 CHDλlT (A) M T4080 2.62 23 2 6 CHDλlT (A) M S-74 2.46 17 A 6 2GT (E) S S-74 2.00 30 B 6 2GT (E) S T4080 2.25 34 C 6 2GT (B) M T4080 2.56 32 D 6 2GT (Q S T4080 2.44 36 E 13 2GT (D) S T4080 2.44 36 F 13 2GT (D) S T2080 2.56 29 Because appropriate commerciaUy-available binder fibers are currently made with cores of 2GT polymer, comparative tests were also made as described hereinafter without binder fibers but using a thermoset resin AM3 as a binder material, and the compression/heat set values are given in Table 2:- TABLE 2 Matrix Item Denier Po P 6 CHDλlT (A) M AM3 2.81 17 X 6 2GT (B) M AM3 2.56 33 Y 6 2GT (E) S AM3 2.36 30 z 13 2GT (D) S AM3 2.4 * 9 35 NOTES: (1) Matrix polymer types:- CHDλlT: from 1,4-cyclohexanedimethanol and terephthalic acid (A) T-211, Eastman Fibers, used for Examples 1 and 2 and Item P 2 G-T: from ethylene glycol and terephthalic acid. (B) T-808, DuPont Fibers, used for Comparisons C and X (C) Not a commercial fiber (but similar to T-88 available from DuPont in Europe) Comparison D (D) H38F, 13 denier, Unitika (Japan), Comparisons E, F and Z (E) H38F, 6 denier, Unitika (Japan), Comparisons A, B and Y (2) Crimp-rypes:- M = Mechanical; S = Spiral (sometimes termed helical). (3) Binder-types:- AU the binder fibers were concentric sheath/ core binder fibers, containing a core of 2G-T surrounded by a sheath of binder material, and were supplied by Unitika Ltd. (4-1-3, Kyutaro-machi, Chuo-ku, OSAKA, 541, Japan). Each of Types 4080 and 2080 has a binder material sheath of 2G-T/2G-I copolymer, but with different proportions of 2G-I, so the binder material copolymers are heat-activatable at different temperatures, about 110 ° C in the case of T4080 and about 210 ° C in the case of T2080. S-74 has a sheath of a new binder material that has not been disclosed by Unitika, but has a distinct melting point (158 °C), so is believed to be crystaUine in contrast to the other binder materials which are not crystalline and do not have distinct melting points, but soften to act as binder materials at about the temperatures indicated. AM3 = Aerotex M-3 -melamine formaldehyde resin sold by American Cyanamid. For each Item in Table 1, the fibers were formed into fiberbaUs (clusters) according to the procedures described in Snyder, U.S. Patent No. 5,218,740. The clusters were made from 80/20 blends (by weight) of the matrix fibers and of the fibers described in Table 1. The molded part was shaped like a cylinder with a 10-inch (25cm) diameter and a 4-inch (10cm) height The entire mold was constructed from perforated carbon steel sheets with 1/8 inch (3.2mm) holes placed at 3/16 (4.8mm) inch centers such that there was about 40% openness. To make molded parts with about a 2.5 lb/ft (40 Kg/m3)density, the cylinder was charged with 0.182 pounds (82 grams) of clusters. A perforated steel plate secured the loose clusters to form a 4-inch (10cm) tall cylinder. The mold, with its charge of clusters, was inserted into ductwork arranged inside an oven to force recirculated heated air through the mold from the bottom to the top. The air pressure was adjusted to between 0.5 and 0.75 inches (12 and 19 mm) water. For Items 1 and B-E (using T4080 binder fiber) the air was heated to 180 deg C, and the sample was removed after one to two minutes when the temperature of the downstream air reached 170 deg C For Item F (using T2080 binder fiber), the air was heated to 220 deg C, and the sample was removed when the temperature of the downstream air reached 210 deg C For Items 2 and A (using S-74 binder fiber), the air was heated to 200 °C, and the sample was removed when the temperature of the downstream air reached 180 °C. Not aU the molded products were exactly 4-inches (10cm) in height when removed from the mold, so the densities reported in the Table were calculated from the actual sample heights. For Table 2, bonding was achieved with melamine formaldehyde resin, Aerotex M3, made by American Cyanamid. A solution was prepared as foUows: 18.4 g of Aerotex M3, 5.9 g of Accelerator MX, and 168 g of water. This solution was intimately mixed with 59 g of clusters, then allowed to drain. The wet clusters were then charged into a solid wall canister with a 6-inch (15cm) diameter. A screen fixed the loft of the wet clusters at 4-inches (10cm). After 20 minutes in an air recirculation oven at 163 deg C. (325 deg F.), the molded parts were dried and cured. Since the binder fibers used in this Example contained a 2G-T core, undesired compression heat/set behavior could be expected as experienced from 2G-T matrix fibers; in other words, the presence of 2G-T could be expected to raise the compression heat/ set values. Also, the 2G-T/2G-I sheaths might soften at the compression heat/set test temperature and contribute to some or all of the heat/ set by allowing the bond points to become mobile. This is why fiberfill clusters in Table 2 were made without such binder fiber and molded by being bonded with Aerotex M3, a melamine formaldehyde thermoset resin, whose properties are known to be relatively insensitive to temperature. Whether bonded with binder fiber or with thermoset resin, the CHDMT clusters had consistently lower heat/ set than 2G- T clusters. Moreover, the lowest heat/set data were obtained (1) when 2G-T polymer was totally excluded from the fiber system (Item P) and (2) when S- 74 binder fiber was used (Item 2). Comparing Comparison Item A with Comparison Item B shows using S-74 vs. T4080 reduced the set somewhat (to 30 from 34) when 2G-T was the matrix fiber (similarly to using AM3 as binder in Item Y in Table 2). Use of CHDMT, however, as in Examples' 1 and 2, reduced the set much more significantly, even when T4080 was used as binder fiber. The added advantage of S-74 vs. T4080 with CHDMT as matrix fiber was much less than when 2G-T was used as matrix fiber, as can be seen, and this is believed to have been because the set was already low with CHDλlT as matrix fiber (80% of such blends). Such binder material preferably has a distinct melting point that is at least 20 °C below the melting point of the matrix fiber (which comprises CHDλlT). Accordingly, preferred molded products are made using such a binder fiber with binder material of softening temperature high enough to resist softening during testing for compression/heat-set testing (for example under ASTM 3574-D), and/ or using CHDλlT polymer both for the matrix fiber and for the core of a sheath/core bicomponent binder fiber. As indicated, reference may be made to the art, such as the Marcus patents, for further detaUs, e.g., the amounts of binder fibers, which wiU depend on the specific application, but wUl generally be about 10-30% by weight of the total weight of fibers. Reverting to the first aspect of the invention, fiberbaUs (clusters) were made essentially similarly as described above for Table 1, except that the feed fiber contained no binder fiber, i.e., was 100% polyester fiberfiU (2 inch cut length). The CHDλlT fiber was T-211 (6 dpf, solid round fiber, same as item A used in Tables 1 and 2), and the 2GT fiber was T-808 (6.5 dpf, single hole hoUow fiber, same as item B used in Tables 1 and 2 above). Whereas item B was "dry", i.e. not coated with a silicone slickener, a commercial product (T-234, 4.25 denier and sUckened), designated as "item X", was also made into clusters by the same process for comparison. The clusters were subjected to comparative bulk measurements and tested for softness by a standard procedure as follows. A 300 gram sample of clusters is charged into a cylinder with a height of 375 mm and an inside diameter of 292 mm. The cylinder is fitted with a circular foot with a 286 mm diameter that is affixed to a Lloyd Instrument Model #LR5K to provide a record of the stress/strain (load vs height) characteristics of the sample while it is being compressed at 508 mm/ min. The sample is pre-compressed to 355 mm. Then during a second cycle, the thickness of the samples is recorded at 0.75, 5.0, 88.5, and 121.5 Newtons force. Of special importance and practical use are the measurements at 5.0 Newtons and 88.5 Newtons as these data correlate, respectively, with the thickness and softness of products such as pillows or cushions to be made from the clusters. Such heights (given in mm, with the standard deviations in parentheses) are set out in Table 3, which shows that the clusters of CHDλlT (A) and 2GT (B) make equivalently lofty pillows, but the CHDλlT clusters are significantly softer to an extent heretofore achieved by use of silicone slickeners, as shown by the values in Table 3 for slickened 2GT (item X). An important advantage of CHDλlT clusters is their reduced sensitivity to flammability, as compared with clusters made from commercial, silicone- slickened 2GT fiber. Table 3 CHDMT (A) 2GT (B) 2GT (X) 5N 25.0(0.5) 26.7(0.8) 23.4 88.5 N 7.6(0.2) 11.4(0.3) 6.1 To summarize, we have found surprising and significant advantages in the compression properties of pillows filled with CHDλlT fiberbaUs, as contrasted with 2G-T. Accordingly, pUlows, cushions and other articles filled with such new fiberbaUs alone, or mixed with other filling material, are expected to be very aestheticaUy desirable, and to have other advantages, as aforesaid.

Claims: Claims:- 1. FiberbaUs, of average diameter 2 to 15mm, consisting essentially of randomly-arranged, entangled, crimped polyester fiberfill having a cut length of 10 to 100mm, characterized in that the polyester is poly (1,4- cyclohexanedimethylene terephthalate). 2. Moldable fiberbaUs, of average diameter 2 to 15 mm, consisting essentially of randomly-arranged, entangled, crimped polyester fiberfill having a cut length of 10 to 100 mm and including binder fiber, characterized in that said polyester fiberfill consists essentially of poly(l,4-cyclohexanedimethylene terephthalate). 3. FiberbaUs according to Claim 2, characterized in that the binder fiber is a bicomponent binder fiber. 4. FiberbaUs according to Claim 3, characterized in that one component of the binder fiber is poly(l,4-cyclohexanedimethylene terephthalate). 5. FiberbaUs according to Claim 4, characterized in that the binder fibers are sheath/core bicomponent fibers with a core of poly(l,4-cyclohexanedimethylene terephthalate) and a sheath of lower melting binder material. 6. FiberbaUs according to any of Claims 2 to 6, characterized in that the binder fiber comprises a binder material with a distinct melting point that is at least 20 C below the melting point of poly(l,4-cyclohexanedimethylene terephthalate) and that is at least 100 °C. 7. Pillows filled with fiberbaUs according to Claim 1.

Inventors: FRANKOSKY MICHAEL STEPHEN, FRANKOSKY, MICHAEL, STEPHEN
Applicants: DU PONT, E.I. DU PONT DE NEMOURS AND COMPANY
Application year: 1994
Main classification: D04H1
IPC codes: B68G1, D04H1